The present invention relates to a method and an apparatus for graphically displaying analysis data by use of the Finite-Element-Method (FEM) and more particularly to a method and an apparatus for displaying a two-dimensional tone picture.
In the conventional method and apparatus for displaying a two-dimensional tone picture of the analysis data by use of the Finite-Element-Method as shown in FIG. 1, each display region according to a boundary value of the analysis data is found in an entire display region before each of the display regions is painted with a predetermined color so as to display a two-dimensional tone picture.
In FIGS. 2A and 2B, an information of adjacent relations of each line segment of the element constructed by nodal points and other elements is set as a flag and an existence of points which accord with a tone boundary value on each line segment of one element is found. When the points exist, the above steps are repeatedly executed in an element adjacent to the line segment including the point so as to obtain a sequence of points. When the sequence of points reaches an end of an entire display region or an element which was judged, the sequence of points is closed to be made into a display region. The set forth steps are executed through all of the elements on the constant boundary value before the above steps are executed through all of the tone boundary values to determine each display regions so as to complete a determination of all display regions. When one display region includes the other display regions, a painting operation is executed in a display region including the other display regions prior to the other display regions so as to complete displaying a two-dimensional tone picture.
However, as shown in FIG. 4, when on line segments of one element adjacent to the line segment including a base point having a value of analysis data equal to a tone boundary value there are two or more found points whose value is equal to the tone boundary value except the base point, two or more tone boundary lines to be connected to the base point with the above two or more found points cause an infinite factor so that determination of a correct display region is impossible.
Otherwise, as shown in FIG. 5, when a nodal point of the element has a tone boundary value, there are a plurality of adjacent elements to the nodal point which cause an infinite factor so that the correct determination of the display region surrounded by the tone boundary lines is also impossible.
Consequently, the prior art has the problems that, when there are large variation in analysis data or available determination of a optional tone boundary value is required, an execution of a correct display of a two dimensional tone picture is impossible.